1. Field of the Invention
The disclosure relates to a phosphor, and in particular relates to a light emitting device utilizing the same.
2. Description of the Related Art
Excitation and emission properties of inorganic phosphors are mainly determined by host materials, activators, and other dopants. Phosphors composed of different host materials, activators or other dopants may have different luminescent properties, such that the composition is the most important factor to tune optoelectronic properties of the phosphors. Mainstream host materials of inorganic phosphors are sulfides, oxides, oxysulfides, or other complex oxides such as silicates, aluminates, phosphates, and the likes. Recently, phosphor development of host materials has been partly moved towards nitrides and oxynitrides. The major activators being used are ions of transition metal elements or rare-earth elements.
A future light source should meet environmental protection requirements of mercury-less/mercury-free, such that a Xe2* excimer lamp and light emitting diode (LED) with high efficiency will possibly become a mainstream future light source. Whether the Xe2* excimer lamp or the LED is adopted, it should probably collocate with a phosphor to convert light from being a short wavelength to being a long wavelength. For example, the Xe2* excimer lamp emits a vacuum ultraviolet (VUV) light having a wavelength of 172 nm, which can be converted by an appropriate phosphor to emit a UV-C light having a wavelength of 200 nm to 280 nm, which may be applied in disinfection, purification, TOC (total organic compounds) reduction, and the likes. The LED has a narrow emission band, which can be converted by an appropriate phosphor to complete a white light emitting diode, which may be applied in illumination, displays, and the likes. Accordingly, the Xe2* excimer lamp and the LED need appropriate phosphors. However, conventional phosphors excitable by the VUV light from the Xe2* excimer lamp are rare, and conventional phosphors excitable by the LED are bounded by patents, respectively. Accordingly, developments of novel phosphors are still called for.